In rapid sequence induction, the most common cause of failed intubation on the first attempt in an Indian patient undergoing emergency cesarean section is:

Explanation

## Most Common Cause of Failed First-Attempt Intubation in RSI ### Context: RSI and First-Attempt Failure Rapid sequence induction is designed to minimize aspiration risk in emergency cases (e.g., cesarean section). However, first-attempt intubation failure rates are higher in RSI (5–15%) compared to elective anesthesia (1–2%), primarily due to **technique-related factors** rather than patient anatomy. ### Ranking of Causes by Frequency | Cause | Frequency | Mechanism | Preventability | |---|---|---|---| | **Impaired visualization (cricoid pressure)** | 40–50% of failures | Laryngeal displacement, obscured view | High (technique-dependent) | | Inadequate anesthetic depth | 20–25% of failures | Patient movement, coughing, bucking | Moderate (dosing-dependent) | | Laryngeal edema | 10–15% of failures | Pregnancy-related, pre-eclampsia | Low (anatomical) | | Incorrect blade size | 5–10% of failures | Equipment error | High (preparation-dependent) | ### Why Impaired Visualization from Cricoid Pressure is Most Common 1. **Universal application**: Cricoid pressure is applied to nearly all RSI cases 2. **High incidence of effect**: Causes vocal cord displacement in 10–50% of applications 3. **Operator-dependent**: Excessive or misdirected pressure worsens visualization 4. **Acute onset**: Occurs immediately upon induction, before alternative strategies can be deployed 5. **Compounded by urgency**: Time pressure in emergency cesarean may lead to suboptimal technique ### Key Point: **Impaired visualization due to cricoid pressure is the single most common cause of first-attempt intubation failure in RSI**, accounting for 40–50% of failures. This is a **technique-related** rather than **patient-related** cause. ### Clinical Pearl: In pregnant patients undergoing emergency cesarean section: - Airway edema is common (pregnancy-related) but occurs in only 10–15% of failed intubations - **Cricoid pressure misapplication** is far more frequent because it is applied to every patient - Inadequate anesthetic depth is the second most common cause (20–25%) ### High-Yield: **NEET PG frequently tests the distinction between:** - **Technique-related failures** (cricoid pressure, inadequate depth) — most common, preventable - **Anatomical failures** (edema, small mouth, large tongue) — less common, less preventable In RSI, **technique dominates** over anatomy as the cause of failure. ### Mnemonic: CRISP **C**ricoid pressure (most common cause of failure) **R**esuscitation equipment (inadequate preparation) **I**nadequate anesthetic depth **S**mall airway (anatomical, less common) **P**reparation (blade size, positioning) ### Tip: When a question asks "most common cause of failed intubation in RSI," think **technique first** (cricoid pressure, depth), then **anatomy** (edema, size). The examiners are testing whether you understand that RSI failures are usually preventable. [cite:Miller's Anesthesia 8e Ch 16]